Monday, March 28, 2011

505 Crivello launcher - Zack Marks

(aka single pole double launcher line system)

This past Midwinters Andrew Jones and I decided to try out a new spinnaker pole system. Gonzalo Crivello our sailing team coach inspired the idea and helped implement it. The system is simple. It is just like the double pole system except that two launcher lines go through one pole. Two blocks hanging on the mast launch the pole rather than the traditional ball and spiro. The lazy guy system is still used.

I really liked this system because it allowed us to get all the benefits of a double pole with minimal modification. The only things that we needed to add were two harken 150 aluminum cam cleats, two deck blocks, a new outboard fitting for the pole, two launcher lines (27 ft of 5mm FSE robline was my choice but anything that can be tapered will do), two metal rings, and two hanging blocks on the mast rather than a spiro. Before we began drilling we made sure to consult our friendly North Sails representatives to confirm that we were on track. Ethan and Lin assured us that it could be done and that was all the confidence we needed.

We started by drilling and installing the deck blocks and the cam cleats. We made sure to place a section of G-10 behind the cleats and blocks to act as a backing plate. We then removed our old single spiro (we tried running both lines through it and it didn’t work) and attached a double spiro part borrowed from Ethan. We removed the block on the side of the fitting before attaching it in order to hang our new blocks. This fitting was used simply to hang two blocks from the mast. Anything that you can use to achieve the same effect will be fine. For a new outboard fitting Ethan gave me the number of a local machine shop guy who was able to create some custom delrin fittings. I thought that I knew what I wanted but it wasn’t quite right, more on this later. After this we tapered the launcher lines spliced the rings to the outboard ends and ran them through the pole and the cleats. We were able to finish this about 2 months before midwinters so we had plenty of time to practice. We discovered a few things.

Gybes were very quick. As I said before, we got pretty much all of the benefits of a double pole without the second pole, second topping lift and downhaul. The difference was that because we launched the pole with just blocks rather than a spiro the load of the pole that is usually on the mast was transferred to the deck block, hence the G-10 backing plate. This also makes it a little more difficult to release the pole because it is so loaded up. The good side is that once it is uncleated the pole retracts with no hesitation. Also with no spiro you lose a little bit of effective length on the pole. Another issue was that we did not place the inhaul bungee at the very end of the pole. This allowed the launcher lines to twist around the back of the pole.

In light air, when retracting the pole, sometimes the ring would continue to pull the spinnaker in rather than let it float out. This would make the spinnaker collapse. Other than eliminating as much friction as possible I am not sure of a way around this. The final issue that needs to be resolved is my outboard pole fitting. I got a delrin fitting made, but I did not place a metal ring internally to prevent the fitting from wearing down. Also the rings that I used on the launcher lines were a little bit big. This resulted in the fitting getting transformed a bit such that the ring would kind of sit in the fitting. This was bad because the ring could not spin. Occasionally the ring would be stuck in the middle of the lazy guy and I could not launch the pole anymore or push the pole forward. A better end fitting should solve this issue.

The system worked well at the event. We only had one gybe wipeout and that was because the pole retracted into the vang. I think that with some more modifications to fix the previously mentioned bugs it will work better. Overall we had a great time at midwinters. Everyone should make it down to sail off of sunny Pass-a-Grille beach next year!